I gave a login the right to access certain columns only but he still can see the group columns, whats missing?
You can either edit each group the given login should have access to and open the “Permissions” area, where you may give the login access level 1, 2 or 3 for this single group. If you want to do this for multiple groups it is easier to use “Login permissions” from the Permissions submenu in the group module. Their you’ll be able to edit single logins and select multiple groups he should have access to.